"use strict";

// Do this as the first thing so that any code reading it knows the right env.
process.env.BABEL_ENV = "production";
process.env.NODE_ENV = "production";

// Makes the script crash on unhandled rejections instead of silently
// ignoring them. In the future, promise rejections that are not handled will
// terminate the Node.js process with a non-zero exit code.
process.on("unhandledRejection", err => {
    throw err;
});

// Ensure environment variables are read.
require("../config/env");

const path = require("path");
const chalk = require("react-dev-utils/chalk");
const fs = require("fs-extra");
const webpack = require("webpack");
const configFactory = require("../config/webpack.config");
const paths = require("../config/paths");
const checkRequiredFiles = require("react-dev-utils/checkRequiredFiles");
const formatWebpackMessages = require("react-dev-utils/formatWebpackMessages");
const printHostingInstructions = require("react-dev-utils/printHostingInstructions");
const FileSizeReporter = require("react-dev-utils/FileSizeReporter");
const printBuildError = require("react-dev-utils/printBuildError");

const measureFileSizesBeforeBuild = FileSizeReporter.measureFileSizesBeforeBuild;
const printFileSizesAfterBuild = FileSizeReporter.printFileSizesAfterBuild;
const useYarn = fs.existsSync(paths.yarnLockFile);

// These sizes are pretty large. We'll warn for bundles exceeding them.
const WARN_AFTER_BUNDLE_GZIP_SIZE = 512 * 1024;
const WARN_AFTER_CHUNK_GZIP_SIZE = 1024 * 1024;

const isInteractive = process.stdout.isTTY;

// Warn and crash if required files are missing
if (!checkRequiredFiles([paths.appHtml, paths.appIndexJs])) {
    process.exit(1);
}

// Generate configuration
const config = configFactory("production");

// We require that you explicitly set browsers and do not fall back to
// browserslist defaults.
const { checkBrowsers } = require("react-dev-utils/browsersHelper");
checkBrowsers(paths.appPath, isInteractive)
    .then(() => {
        // First, read the current file sizes in build directory.
        // This lets us display how much they changed later.
        return measureFileSizesBeforeBuild(paths.appBuild);
    })
    .then(previousFileSizes => {
        // Remove all content but keep the directory so that
        // if you're in it, you don't end up in Trash
        fs.emptyDirSync(paths.appBuild);
        // Merge with the public folder
        copyPublicFolder();
        // Start the webpack build
        return build(previousFileSizes);
    })
    .then(
        ({ stats, previousFileSizes, warnings }) => {
            if (warnings.length) {
                console.log(chalk.yellow("Compiled with warnings.\n"));
                console.log(warnings.join("\n\n"));
                console.log(
                    "\nSearch for the " +
                        chalk.underline(chalk.yellow("keywords")) +
                        " to learn more about each warning."
                );
                console.log("To ignore, add " + chalk.cyan("// eslint-disable-next-line") + " to the line before.\n");
            } else {
                console.log(chalk.green("Compiled successfully.\n"));
            }

            console.log("File sizes after gzip:\n");
            printFileSizesAfterBuild(
                stats,
                previousFileSizes,
                paths.appBuild,
                WARN_AFTER_BUNDLE_GZIP_SIZE,
                WARN_AFTER_CHUNK_GZIP_SIZE
            );
            console.log();

            const appPackage = require(paths.appPackageJson);
            const publicUrl = paths.publicUrlOrPath;
            const publicPath = config.output.publicPath;
            const buildFolder = path.relative(process.cwd(), paths.appBuild);
            printHostingInstructions(appPackage, publicUrl, publicPath, buildFolder, useYarn);
        },
        err => {
            const tscCompileOnError = process.env.TSC_COMPILE_ON_ERROR === "true";
            if (tscCompileOnError) {
                console.log(
                    chalk.yellow(
                        "Compiled with the following type errors (you may want to check these before deploying your app):\n"
                    )
                );
                printBuildError(err);
            } else {
                console.log(chalk.red("Failed to compile.\n"));
                printBuildError(err);
                process.exit(1);
            }
        }
    )
    .catch(err => {
        if (err && err.message) {
            console.log(err.message);
        }
        process.exit(1);
    });

// Create the production build and print the deployment instructions.
function build(previousFileSizes) {
    // We used to support resolving modules according to `NODE_PATH`.
    // This now has been deprecated in favor of jsconfig/tsconfig.json
    // This lets you use absolute paths in imports inside large monorepos:
    if (process.env.NODE_PATH) {
        console.log(
            chalk.yellow(
                "Setting NODE_PATH to resolve modules absolutely has been deprecated in favor of setting baseUrl in jsconfig.json (or tsconfig.json if you are using TypeScript) and will be removed in a future major release of create-react-app."
            )
        );
        console.log();
    }

    console.log("Creating an optimized production build...");

    const compiler = webpack(config);
    return new Promise((resolve, reject) => {
        compiler.run((err, stats) => {
            let messages;
            if (err) {
                if (!err.message) {
                    return reject(err);
                }

                let errMessage = err.message;

                // Add additional information for postcss errors
                if (Object.prototype.hasOwnProperty.call(err, "postcssNode")) {
                    errMessage += "\nCompileError: Begins at CSS selector " + err["postcssNode"].selector;
                }

                messages = formatWebpackMessages({
                    errors: [errMessage],
                    warnings: []
                });
            } else {
                messages = formatWebpackMessages(stats.toJson({ all: false, warnings: true, errors: true }));
            }
            if (messages.errors.length) {
                // Only keep the first error. Others are often indicative
                // of the same problem, but confuse the reader with noise.
                if (messages.errors.length > 1) {
                    messages.errors.length = 1;
                }
                return reject(new Error(messages.errors.join("\n\n")));
            }
            if (
                process.env.CI &&
                (typeof process.env.CI !== "string" || process.env.CI.toLowerCase() !== "false") &&
                messages.warnings.length
            ) {
                console.log(
                    chalk.yellow(
                        "\nTreating warnings as errors because process.env.CI = true.\n" +
                            "Most CI servers set it automatically.\n"
                    )
                );
                return reject(new Error(messages.warnings.join("\n\n")));
            }

            return resolve({
                stats,
                previousFileSizes,
                warnings: messages.warnings
            });
        });
    });
}

function copyPublicFolder() {
    fs.copySync(paths.appPublic, paths.appBuild, {
        dereference: true,
        filter: file => file !== paths.appHtml
    });
}
